Israeli and Palestinian presidents will meet in an unprecedented prayer meeting with Pope Francis, a gesture he hopes will ''re-create a desire, a possibility'' of eventually relaunching the Middle East's stalled peace process.

The Vatican has played down any expectations that the Sunday evening meeting between Shimon Peres and Mahmoud Abbas - billed as a ''pause from politics'' - will lead to any immediate breakthroughs in the region's tortuous problems and says it is not meddling in regional issues.

''No one is presumptuous enough to think peace will break out on Monday,'' said Father Pierbattista Pizzaballa, a Church official in charge of Catholic sites in the Holy Land and a key organiser of the encounter.

''The intention of this initiative is to re-open a road that has been closed for some time, to re-create a desire, a possibility, to make people dream,'' he said, adding that the pope does not want to get involved in details of issues such as borders or settlements.

Israeli Prime Minister Benjamin Netanyahu, the key Israeli decision-maker, is not attending and he refuses to deal with the Palestinian unity government, backed by Hammas Islamists, that Abbas swore in last Monday.

Peres is due to leave office next month.

But the fact that Francis' bold move has managed to bring the two presidents together shows his desire to engage political leaders on global issues, offering inter-religious dialogue as a building block.

The meeting is taking place more than a month after US-led peace talks collapsed amid bitter mutual recrimination.

The pope, in his weekly Sunday address in St. Peter's Square, said he hoped faithful of all religions ''will unite themselves spiritually to our plea''.

The pope made his surprise invitation to the two heads of state while he was in the Holy Land last month.